Effect of Initial Concentration on Adsorption-Desorption Characteristics and Desorption Hysteresis of Hexachlorobenzene in Soils

作     者：GAO Hong-Jian JIANG Xin 

作者机构：School of Resources and Environmental Science Anhui Agricultural University Hefei 230036 (China) State Key Lab of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) 

出 版 物：《Pedosphere》 (土壤圈（英文版）)

年 卷 期：2010年第20卷第1期

页      面：104-110页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 070602[理学-大气物理学与大气环境] 0706[理学-大气科学] 0703[理学-化学] 

基　　金：Project supported by the Open foundation of the State Key Lab of Soil and Sustainable Agriculture, Institute of SoilScience, Chinese Academy of Sciences (No. 0812000037) the Scientific Research Starting Foundation for the ReturnedOverseas Chinese Scholars, Ministry of Education, China (No. 20091001) the National Science and Technology PillarProgram During the 11th Five-Year Period of China (No. 2009BADA6B04) 

主　　题：Freundlich equation sorption coefficients sorption isotherms 

摘      要：Adsorption and desorption are important processes that influence the transport, transformation, and bioavailability of hexachlorobenzene (HCB) in soils. To examine the adsorption-desorption characteristics of HCB, equilibrium batch experiments were carried out using two soils (red soil and paddy soil) with different initial HCB concentrations (0.25, 0.50, 0.75, 1.00, 1.50, 2.50, 3.50, and 5.00 mg L-1 ) by using 0.01 mol L-1 calcium chloride as the background solution. The successive desorption experiments (48, 96, 144, 192, and 240 h) were conducted after each adsorption equilibrium experiment. The results revealed that adsorption and desorption isotherms of HCB on two soils were nonlinear, which can be best described by the Freundlich equation with the square of the correlation coefficient (r 2 ) ranging from 0.97 to 0.99. Desorption of HCB from the two soils exhibited hysteresis at all HCB concentrations because the Freundlich desorption coefficients were always higher than the Freundlich adsorption coefficients. The hysteretic effect was enhanced with increasing initial HCB concentration, and positive hysteresis was observed at different concentrations.